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package com.srcptit.trainning.thompv.btvn1;
import java.util.Scanner;
/**
 *
 * @author SONY
 */
public class Bai1Muc1 {
    static boolean ngto(long n)
    {
        long m=(long)Math.sqrt(n);
        if(n<2) return false;
        for(int i=2;i<=m;i++)
           if(n%i==0) return  false;
           return true;
    }
    public static void main(String[] args)
    {
        Scanner sc=new Scanner(System.in);
        long a;
        a=sc.nextLong();
        if(ngto(a)) System.out.println("Day la so nguyen to");
        else System.out.println("Day ko phai la so nguyen to");
    }
    
}
